Solubility measurements will be continued on octacalcium phosphate and on hydroxyapatite and tooth enamel in the presence of CO2. The uptake of F ions by the surfaces of hydroxyapatite crystals as functions of pH, F concentration and time will be investigated. Studies will be made on the effects of Galvani potentials on the transport of ions through membranes that simulate the to the surface-plaque layer. Laboratory and pilot clinical studies will be made on a new remineralization procedure. Crystal structure analyses will be made on a monomer which expands on polymerization, on an unusual fluoride compound that appears to have promise as a topical fluoridation product, on a strontium phosphate that may be calcium phosphate nucleation analog, and on several calcium phosphate compounds containing other components.